JP3465361B2 - Extrusion molding method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion molding method, and more particularly to an extrusion molding method in which the thickness of a cylindrical molded product is not uneven.
The present invention relates to an extrusion method for controlling a thickness distribution. [0002] Conventionally, it has been practiced to control the temperature distribution near the extrusion port of an extrusion die to control the thickness distribution of an extruded product. In such an extrusion molding method, a plurality of heating means such as heaters are provided near the extrusion port, and the temperature distribution near the extrusion port is controlled by individually controlling each of the heating means. [0003] However, in the above-mentioned conventional example, it may be difficult to control the temperature distribution quickly, and the thickness of the extruded product may not be controlled with high accuracy. The reason is that the temperature can be easily increased by increasing the electric power supplied to the heater, but when cooling, the heater is turned off to allow the heater to cool naturally. That is, the cooling is rate-determining, and it is difficult to quickly control the temperature distribution. Further, even if one heater is turned off, the temperature is hardly lowered due to the influence of the heater next to the heater. Therefore, even when the thickness of the extruded product is detected, the result of the detection does not immediately lead to the control of the temperature distribution of the extrusion die, and during this time, the thickness of the extruded product is not properly controlled. Loss in continuous molding. The present invention has been made to solve the above problems, and an object of the present invention is to control the temperature distribution near the extrusion port of an extrusion die quickly and accurately to obtain an extruded product. An object of the present invention is to provide an extrusion molding method capable of controlling the thickness with high precision. According to a first aspect of the present invention, there is provided a method for detecting a thickness distribution of a molded product, and controlling a temperature distribution of an extrusion die based on the detected result. In an extrusion molding method for controlling the thickness distribution of a molded product to be constant, an extrusion die constituted by a cylindrical outer die and an inner die is used .
A plurality of heating means are provided around the outer diameter die, and the outer circumference of the outer diameter die
From the extrusion die opening to form a communication passage.
For the extruded product extruded through the outlet of this communication passage,
And the cooling fluid is directed toward the outlet of the communication passage.
The present invention is characterized in that an extrusion molding method is characterized by using a cooling means that is caused to flow, and individually controlling each heating means or cooling means. The invention according to claim 1 is characterized in that a heating means is provided on the outer periphery of the outer diameter die, and a cooling means is provided between the heating means and the inner surface of the outer diameter die. In the invention as a reference example , the outer diameter die is divided into a plurality of blocks by grooves extending from the outer surface to the inner surface of the outer diameter die, and each block is controlled as a unit. The invention as a reference example is characterized in that a heating means is provided on an outer diameter die and a cooling means is provided on an inner diameter die. In the invention of the reference example , the outer diameter die is provided with heating means, and the outer diameter die and the inner diameter die are provided with cooling means. In the invention of the reference example , the cooling means is arranged at a substantially constant interval from the inner surface of the outer diameter die or the outer surface of the inner diameter die. According to the first aspect of the present invention, a communication path is provided from the outer periphery of the outer diameter die toward the extrusion opening of the extrusion die, and the outlet of the communication path is formed toward the extruded product to be extruded. Further, a cooling means for flowing the cooling fluid toward the outlet direction of the communication passage is used. [0013] In the invention as a reference example, each block is insulated by filling a groove with a heat insulating material. According to the first aspect of the present invention, the extrusion die includes a cylindrical outer diameter die and an inner diameter die, and the molding material is extruded through a gap between the outer diameter die and the inner diameter die. A cylindrical extruded product is formed. At this time, by individually controlling a plurality of heating means or cooling means provided in the extrusion die, a temperature distribution is given in a direction orthogonal to the extrusion direction of the extrusion die. By such control, a portion having a high temperature is extruded with a large thickness, and a portion having a low temperature is extruded with a small thickness to control the thickness of the extruded product. When the temperature is to be lowered, the cooling means can be used for rapid cooling. According to the first aspect of the present invention, since the cooling means is disposed between the heating means and the inner surface of the outer diameter die and is close to the flow path of the molding material, the cooling is rapidly performed. In the invention of the reference example , each block is insulated by the groove dividing the outer diameter die into a plurality of blocks, and the temperature of each block is controlled independently. It has become difficult. In the invention as the reference example , the cooling is rapidly performed because the cooling means provided on the inner diameter die is close to the flow path of the molding material. In the invention of the reference example , since the outer diameter die and the inner diameter die both contribute to cooling, cooling is performed more quickly. In the invention of the reference example , the cooling means are arranged at a substantially constant interval from the inner surface of the outer diameter die or the outer surface of the inner diameter die and are at a certain distance from the flow path of the molding material. It works equally. According to the first aspect of the present invention, since the cooling fluid passes through the extrusion port and directly hits the extruded molded product, the molded product is also cooled. In the invention as the reference example , each block is more reliably insulated by the heat insulating material filled in the groove. An embodiment of the present invention will be described below with reference to the accompanying drawings. In the extrusion molding method of this embodiment, the thickness distribution of the extruded product 3 is detected, the temperature distribution of the extrusion die is controlled based on the detection result, and the thickness distribution of the molded product is controlled to be constant. In this extrusion molding method, a plurality of heating means 7 and cooling means 8 are provided in the extrusion die 1 and each heating means 7 or cooling means 8 is individually controlled. Extrusion mold 1
Is formed by a cylindrical outer die 10 and an inner die 11 inserted into the outer die 10. The molding material is extruded through a gap between the outer die 10 and the inner die 11. It has become so. First, a basic embodiment of the extrusion molding method according to the present embodiment will be described with reference to FIGS. 1 and 3 are perspective views schematically showing the configuration and structure of an extrusion die 1 of the extruder, and FIG. 4 is a side view showing one part of the extrusion die 1. FIG. 2 is a perspective view schematically showing an entire extruder for performing the extrusion method of this embodiment. In FIG. 2, reference numeral 1 denotes an extrusion die, which comprises a cylindrical outer die 10 and an inner die 11. The molding material is introduced from the charging port 2, heated and extruded from the extrusion die 1 as an extruded product 3. The extruded product 3 is cooled by passing through a cooling water tank 4, and its thickness is detected by a thickness measuring device 5. The detection result of the thickness is sent to the control device 6. In the thickness measuring machine 5, a sensor section 5a comprising an ultrasonic oscillator and a detecting section uses the ring-shaped portion of the thickness measuring machine 5 as a guide to move the outer periphery of the extruded product 3 to 3 mm.
It is configured to rotate by 60 degrees and detect the thickness distribution at eight representative points. In addition, the mechanism detects the reflection of the ultrasonic wave emitted from the ultrasonic oscillator from the outer peripheral surface and the inner peripheral surface of the extruded product by the detection unit, and obtains the thickness from the difference. As shown in FIG. 1, a plurality of heating means 7, cooling means 8 and temperature measuring means 9 are provided on the extrusion die 1 of the extruder.
Further, respective heating means 7, cooling means 8, and temperature measuring means 9
Are provided at corresponding positions. Then, the control device 6 compares the detection result of the thickness of the extruded product 3 with the measurement result of the temperature of the extrusion die 1 by the temperature measuring means 9,
The heating means 7 and the cooling means 8 are arranged so as to increase the temperature of the corresponding part of the extrusion die 1 when the thickness is insufficient, and to decrease the temperature when the thickness is too large. Controlling. For example, when lowering the temperature, the heating means 7
Is turned off and the cooling means 8 is turned on. Conversely, when the temperature is raised, the heating means 7 is activated. In the case of such a long cylindrical extruded product 3, since there is bending when there is uneven thickness, it is necessary to always extrude the product with a constant thickness. Note that this uneven thickness occurs due to abrasion of the extrusion port of the extrusion die 1 or a change in the material lot. FIG. 1 is a perspective view schematically showing the configuration of the extrusion die 1 provided with the above-mentioned heating means 7, cooling means 8 and temperature measuring means 9, and FIG. 3 is an exploded perspective view showing the internal structure. It is. As shown in FIG. 3, the extrusion die 1 has a cylindrical outer diameter die 10 having a cylindrical inner diameter die 11 tip inserted therein, and is integrally fixed together with a cylindrical die part 12. is there. Also, the molding material passes through the gap between the die part 12 and the spider 13 of the inner diameter die 11, and the outer diameter die 10
It is extruded from the gap between the inner die 11 and the inner diameter die 11. FIG. 4 shows the spider 13. The spider 13 is formed on the outer periphery of the inner diameter die 11 as a column for holding the flange 11a. In FIG. 1, the outer diameter die 10 is provided with a heating means 7, a cooling means 8, and a temperature measuring means 9. As the heating means 7, an electric heater or the like provided on the outer periphery of the outer diameter die 10 is used. The cooling means 8 forms a communication passage 8a communicating from the outer periphery of the outer diameter die 10 to the outer periphery of the extrusion opening of the extrusion die 1 so as to be a passage through which a cooling fluid such as air or cooling water passes. It can be configured to allow fluid to pass through and cool. In addition, as the cooling fluid, air or the like may flow in the direction of the extrusion port,
Further, water or the like cooled by the cooling device 8b may be circulated in the direction of the extrusion port or in the opposite direction. Then, the cooling amount is adjusted by changing the temperature or the flow rate of the cooling fluid. As the temperature measuring means 9, a thermocouple type thermometer or the like is used. The heating means 7, the cooling means 8, and the temperature measuring means 9 are divided into a plurality of blocks 15 from the center of the outer diameter die 10 toward the outer periphery, and provided in each block 15. The temperature of these blocks 15 is individually controlled. As described above, by individually controlling the plurality of heating means 7 or cooling means 8 provided in the extrusion die 1, a temperature distribution is given in a direction orthogonal to the extrusion direction of the extrusion die 1. Can be And, due to this temperature distribution,
The high temperature part is extruded with a large thickness, and the low temperature part is extruded with a small thickness to control the thickness of the extruded product. Therefore, the thickness of the extruded product 3 can be controlled with high precision by detecting the thickness of the extruded product 1 and giving a temperature distribution to the extrusion die 1 corresponding to the thickness. The control of the thickness is to make the thickness uniform or to a desired thickness. The temperature of the extrusion die 1 is controlled by a heater or the like when the temperature is raised, and by cooling air or the like when the temperature is lowered. The temperature distribution can be given to the extrusion die 1 quickly in response to the detection result of the thickness of the product 3, and the thickness of the extruded product 3 can be controlled and molded without loss time. In the following, some references of the cooling means 8 will be referred to.
Reference Examples (FIGS. 5, 6, 7, 9, and 10)
The clear embodiment (FIG. 8) will be described in more detail. FIGS. 5 to 7 as reference examples explain the position where the cooling means 8 is provided, and are drawings showing the extrusion die 1. FIG. 5 shows an example in which the cooling means 8 is provided on the outer diameter die 10 as schematically described above, FIG. 6 shows an example in which the cooling means 8 is provided on the inner diameter die 11, and FIG.
2 shows an example provided on the inner diameter die 11 and the inner diameter die 11. FIG. 5A is a side view, and FIG. 5B is a longitudinal sectional view. As shown in this figure, eight heating means 7 are provided at equal intervals on the outer periphery of the outer diameter die 10 on the extrusion port side, and eight are also provided on the outer periphery on the connection side with the inner diameter die 11. Further, the cooling means 8 forms a communication passage 8a passing below the heating means 7 on the extrusion port side of the outer diameter die 10, and allows a cooling fluid to flow from a cooling device 8b provided outside, so that the cooling fluid is formed into a molding material. In the vicinity of the flow path, so that cooling can be performed quickly. In FIG. 6, (A) is a side view, and (B)
Shows a longitudinal sectional view, and (C) shows an AA section in the figure of (B). The example shown in this figure uses a cooling means 8 different from that of FIG. That is, as shown in this figure, the communication passage 8a is formed so that the inner diameter die 11 passes through the spider 13 from the outer periphery of the flange portion of the inner diameter die 11.
Are formed in the direction of the extrusion port along the outer periphery of the inner diameter die 11.
That is, also in this case, since the cooling fluid flows along the outer periphery of the inner diameter die 11 close to the flow path of the molding material, the cooling is quickly performed. FIG. 7 shows an example in which the cooling means 8 shown in FIG. 5 and FIG. 6 are simultaneously performed. The example shown in FIG. 7A is a side view of the extrusion die 1 as viewed from the extrusion opening. In this example, the cooling means 8 for the outer diameter die 10 and the inner diameter die 11 is replaced with the heating means 7.
In addition, this is an example in which the components are arranged on a straight line from the center of the extrusion die 1 toward the outer peripheral direction. In this case, since the cooling can be performed from both directions of the inner surface and the outer surface of the flow path of the molding material,
Cooling will occur very quickly. FIG. 7B is a side view of the extrusion die 1 as viewed from the extrusion port, similarly to FIG. 7A. In this example, the cooling means 8 provided on the inner diameter die 11
Are staggered. That is, the outer diameter die 10 is placed on a straight line from the center of the extrusion die 1 toward the outer periphery.
The cooling means 8 provided on the inner diameter die 11 is disposed together with the cooling means 8 provided on the inner diameter die 11.
It is arranged on a straight line at a position between the cooling means 8 provided at zero. In this case, it is possible to control cooling that is finely divided in the circumferential direction. The cooling means 8 described above is preferably arranged at a substantially constant distance from the inner surface of the outer diameter die 10 or the outer surface of the inner diameter die 11. According to such an arrangement, the cooling means 8 is formed by molding. Since it is at a certain distance from the material flow path, each cooling means functions equally and the extrusion mold 1
Can be reliably cooled to the same extent. FIG. 8 shows a cooling means 8 according to an embodiment of the present invention, in which the shape of the communication passage 8a is devised.
This figure shows the extrusion die 1, (A) shows a side view, and (B) shows a longitudinal sectional view. As shown in this figure, the communication path 8a extends from the outer periphery of the outer diameter die 10 toward the extrusion port of the extrusion die 1.
Is formed so that the cooling fluid directly hits the extruded product 3 exiting the extrusion port. In the case of FIG. 6 which is a reference example in which the cooling means 8 is provided on the inner diameter die 11, similarly, the communication passage 8 a is formed so as to be inclined in the direction of the extrusion port of the extrusion die 1, and the cooling fluid is formed by the extrusion port Directly from the extruded product 3 exiting the slab. Therefore, the extruded product 3 is also cooled by the cooling fluid that has cooled the extrusion die 1, and the cooling fluid of the extrusion die 1 can be used for cooling the extruded product 3. I have. Next, an embodiment relating to the shape of the external die 10 will be described with reference to FIGS. 9 and 10 which are reference examples . These figures show the upper left quarter of the side view of the extrusion die 1 as viewed from the extrusion port. In the extrusion die 1 shown in FIG. 9, the outer diameter die 10 is divided into a plurality of blocks 15 by grooves 14 extending from the outer surface to the inner surface of the outer diameter die 10. The temperature is controlled. That is, the outer diameter die 11 is connected to the plurality of blocks 1
The groove 14 divided into 5 makes it hard to be affected by the heat of the adjacent block 15 and controls the temperature of the extrusion die 1. Therefore, the extrusion molding method is such that the temperature distribution of the extrusion die 1 can be obtained appropriately and quickly. The extrusion die 1 shown in FIG. 10 is the same as the groove 1 shown in FIG.
4 is further filled with a heat insulating material 16 to insulate each block 15. Therefore, since each block 15 is more reliably insulated, the extrusion molding method in which the temperature distribution of the extrusion die 1 can be obtained appropriately and promptly is provided. The shape of the extrusion die 1 shown in FIGS. 9 and 10 is used to better obtain the temperature distribution of the extrusion die 1.
Even in the case where no 6 is provided, the temperature control of the extrusion die 1 is sufficiently performed in many cases. Further, in all the embodiments described above, examples are shown in which the extrusion die 1 is formed by extruding an extruded product 3 having a circular cross section. However, the present invention is not limited to the circular cross section. Can be applied to the extruded product 3. As described above, according to the present embodiment,
Since the cooling means 8 is provided together with the heating means 7, the temperature distribution in the vicinity of the extrusion port of the extrusion die 1 is quickly and accurately controlled,
This is an extrusion method capable of controlling the thickness of the extruded product 3 with high precision. According to the first aspect of the present invention, a temperature distribution is given in a direction perpendicular to the extrusion direction of the extrusion die, and in this temperature distribution, a portion having a high temperature is extruded with a small thickness.
The low temperature portion is extruded with a large thickness to control the thickness of the extruded product. Therefore, the thickness of the extruded product can be controlled with high accuracy by detecting the thickness of the extruded product and giving a temperature distribution to the extrusion die so as to correspond to this thickness. This control of the wall thickness can make the wall thickness constant or a desired thickness. Further, in the temperature control of the extrusion die, since the temperature rise and fall are both performed rapidly, it is possible to give the temperature distribution to the extrusion die in response to the detection result of the thickness of the extruded product quickly. It is possible to control the thickness of the extruded product without loss time and perform molding. According to the first aspect of the present invention, the cooling means is disposed near the flow path of the molding material, and the cooling is rapidly performed.
The molding can be performed without the loss time of the temperature control of the extrusion die. In the invention of the reference example, the temperature of the extrusion die is controlled by blocking the heat of the adjacent block by making the outer diameter die divided into a plurality of blocks so as to block the heat of the adjacent block. You. Therefore, the molding method is capable of appropriately and quickly changing the temperature distribution of the extrusion die. In the invention of the reference example, since the cooling means is disposed close to the flow path of the molding material and the cooling is rapidly performed, the molding can be performed without the loss time of the temperature control of the extrusion die. . According to the invention as a reference example , both the outer diameter die and the inner diameter die contribute to cooling and are rapidly cooled, so that the molding can be performed while omitting the loss time of the temperature control of the extrusion die. it can. In the invention of the reference example, since the cooling means is located at a fixed distance from the flow path of the molding material, the respective cooling means function equally, and each part of the extrusion mold is surely cooled to the same extent. can do. According to the first aspect of the present invention, the cooling fluid of the extrusion die can be used for cooling a molded product. In the invention of the reference example , each block is more reliably insulated by the heat insulating material filled in the groove. Therefore, the temperature of the extrusion die is controlled with less influence of the adjacent block, and the temperature distribution of the extrusion die is obtained more appropriately and quickly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view schematically showing a structure of an extrusion die according to an embodiment of the present invention. FIG. 2 is a perspective view schematically showing an entire extruder for performing the embodiment. FIG. 3 is an exploded perspective view schematically showing a structure of an extrusion die in the embodiment. FIG. 4 is a side view showing one part of the above extrusion die. [5] a view showing a position where the cooling means definitive in Reference Example, (A) is a side view as viewed from the extrusion port of the extrusion die,
(B) shows a longitudinal sectional view. 6A and 6B are views showing positions where cooling means are provided in the reference example, where FIG. 6A is a side view as viewed from an extrusion opening of an extrusion die, and FIG.
Shows a longitudinal sectional view, and (C) shows an AA sectional view in (B). FIGS. 7A and 7B are views showing a position where a cooling means is provided in the reference example, and FIGS. 7A and 7B are side views as seen from an extrusion opening of an extrusion die. 8A and 8B are diagrams showing the shape of the cooling means in the embodiment of the present invention, wherein FIG. 8A is a side view as viewed from the extrusion opening of the extrusion die, and FIG. 8B is a longitudinal sectional view. FIG. 9 is a side view of the definitive extrusion die to the reference example from the direction of the extrusion port. FIG. 10 is a side view of the definitive extrusion die to the reference example from the direction of the extrusion port. [Description of Signs] 1 Extrusion mold 2 Input port 3 Extruded product 4 Cooling water tank 5 Thickness measuring instrument 6 Control device 7 Heating means 8 Cooling means 9 Temperature measuring means 10 Outer die 11 Inner die 12 Die parts 13 Spider 14 Groove 15 Block 16 Insulation

Continuation of the front page (56) References JP-A-48-17855 (JP, A) JP-A-59-212234 (JP, A) JP-A-60-178019 (JP, A) JP-A-62-11623 (JP, A) JP-A-63-272519 (JP, A) JP-A-3-246022 (JP, A) JP-A-3-197020 (JP, A) JP-A-3-59821 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 47/00-47/96

Claims (1)

(57) [Claims] [Claim 1] Detecting the thickness distribution of a molded article, controlling the temperature distribution of an extrusion die based on the detection result, and controlling the thickness distribution of the molded article to be constant. in the extrusion molding method of the outer diameter of the extrusion die composed of a cylindrical outer diameter die and the inner diameter die
A plurality of heating means are provided on the outer periphery of the die, and
A communication passage is provided by inclining in the direction of the extrusion port of the extrusion die.
The outlet of the communication passage is directed toward the extruded product to be extruded.
So that the cooling fluid flows toward the outlet of the communication passage.
Extrusion method characterized by using the cooling means are Unishi, individually controlling the respective heating means or cooling means.